Sound regenerating apparatus



Sept. .1931. R. c. DARNELL ,933

SOUND REGENERATING APPARATUS Filed Dec. 28, 1925 2 Sheets-Sheet lSvweutoz m 7867 CJd/n e22 Sept. 8, 1931. R. c. DARNELL SOUNDREGENERATING APPARATUS Filed Dec. 28 1925 2 Sheets-Sheet 2 attoznu vanon Wow Z6): 6 iarzzedz lei port.

Patented Sept. 8, 1931 ED gzsi'mrs s mars NT UFFIZCTE 'iALREXC..'DARNELL,;OF .IROYALv OAK, .MICHIGAN,.ASSIGN.OR OFQIIE-THIRD TOHAROLD. B. l'PIITNAIVL.0F..DETROIT;ZMICHIGAN,..A1\TD -ONE-THIRD TOFRANK- L. 'IwZUNSON, OF

. WARREN, MICHIGAN sounnnsennnnamme APBARATUS.1.ApplicationrfiledDecember 28, 1925.-Seria1 Ne.-77,946.

This invention relates tosound regenerat.

ing apparatus and is particularly directed to the attainment of a-directpropagation,

in free air,"of self sustaining sound Waves a 6 substantiallycorresponding in intensity and quantity. as Well as=in timbre andmellowness and other -qi'ialities, to the originally produced soundwaves. The invention re-' "lates more particularly to a reproducing or10 sound regenerating device of the cone .dia-

phragm or tympanum type.

'-In* the present day; development of this art as now extensivelycommercially exploited many types of cone diaphragms have been:produced. YThese' devices. show a marked similarity in design as wellas-in efficiency as regards tone quality and faithfulnessin-reproductionbut in the majority "of such devices notable defects are apparent.Exhaustivestudy of the problems presented hasjdiscloSedthe causes andfundamental i-deficiencies in these heretofore known types which resultin their inefiicient operation.

' the diaphragm adjacent its peripheral sup- It has been determinedthat. this is the result of a .too; rigid or nonflexible mounting of thediaphragnior tympanum.

This rigidity of-constru'ction resultedfirstv from the angle 'ofprojection of the cone with reference toits supportingframez andsecondly because of the nonl-flexibility'of the connection between. thetympanum and. the ,tympanunr support. 1 Efficiency' .in tonal squantityv and quality as well as faithfulness in reproduction istherefoiebest obtained with a tympanumcapa'ble'of freely vibratfstructure wherein the aforementionenl objections are eliminated and theadvantages ing both forward and aft.

Another structural feature essential to 'eflt. cient operation is theconnection betweenthe diaphragm operatingelement and the *tympanum.While it is customary to form thetympanunrof a light'vibratile material"nevertheless a metallic connection between lic tones; It is thereforeessential that the connection between the diaphragm actuating elementand the tympannm be of a mat 'ial which functions as tone modifier, dade';

or rattle preventative whereby the mellow-- ness and richness of thetones is maintained. For accomplishingthis it is essential that somenon-metallic substance be employed in this connection.

In conical tympanums as now commercial-- ly produced it is almostuniversally the practice to connect the diaphragm actuating; element tothe tympanum at the apex thereof.

'- While such constructions operate more or less efficientlynevertheless the relatively weak and minute vibrations-are transmittedto the tympanum-at the point of its great est rigidity." In conicaltympanums the niost flexible point on any litdlitl lllle drawn fromtheapex to the periphery is midway or in tel-mediate between theapex andthe periphery of the cone and consequently if the sound vibrations aretransmitted to the tymfpanum atsuch a. point, or in conical diaphragmson a circui'nferential line intermc I diate theapex andperiphery, .thenthe diaphragm Will function more responsively as ithevibrationsiareimparted thereto at its most flexiblecircumferential point.

It has: also been found that it is most eih-- cientto rigidly supportthe tympanuni pe- "ri'phe'rall'y but that inellownessof tone andfaithfulness in reproduction is best obtained first when the tympanunisupporting frame is 'of. anon-metallic material and second;-

when .such supporting frame is peri fiherally spaced with reference tothe .efl'ectivediaineter- 'of the tympanum.

.This invention .has5therefore, among its objects to produce a tympannmor cone type diaphragm having incorporated therein.

"erall s aced S117 iortin frame. The combined width of these projectionsis only fifty percent or less of the effective outside diameter of thetympanum, these projections furthermore being extended perpendicularlyto the axis of the conical tympanum or angularly with reference to thewalls of the cone. Furthermore the invention contemplates the use ofnon-metallic material in the connection between the actuating elementand the diaphragm and'also contemplates the use of a relatively invertedcone shaped member rigidly connected to the conical tympanum on acircumferential line preferably intermediate the apex and periphery ofthe tympanum, the diaphragm actuating element in such a constructionbeing connected to the apex of this inverted cone.

Various other objects, advantages and novel details of construction ofthis invention will be made more apparent as this description proceedsespecially when considered in connection with the accompanying drawingswherein:

Fig. 1 is a side elevation of a tympanum constructed in accordance withthis invention,

Fig. 2 is a front elevation thereof.

F ig. 3 is an enlarged vertical fragmentary section through thetympanum.

Fig. 4 is a fragmentary sectional elevation taken substantially on theplane indicated by line 44 in Fig. 3, and

Fig. 5 is a View similar to Fig. 3 of a slightly modified form ofconstruction.

Referring now particularly to the drawings wherein like referencecharacters indicate like parts it will be noted that there isillustrated a conical tympanum or diaphragm 1O constructed preferably ofa light vibratile material and supported adjacent its periphery by meansof a frame 11 and a binding ring 12. The frame 11 is connected to asupporting arm 13 preferably by means of a plurality of radial arms 14.The effective outside diameter of the tympanum 10 is indicated by thereference character 15, it being noted that this peripheral line 15 ofthe tympanum is spaced from the inside edge of the supporting frame 11.Supporting connection between the tympanum 10 and frame 11 isaccomplished by means of a plurality, that is, two or more projections16, which in the form of construction herein shown are made integrallywith and a part of the tympanum 10. However, these extensions orprojections may obviously be formed separate and connected to theperiphery of the tympanum. It is essential, however, that the totalwidth of the combined projections 16 not exceed and be preferably lessthan fifty percent of the effective periphery of the tympanum.Furthermore it is of extreme importance that these extensions 16, bearranged perpendic ular to the axis of the tympanum or, in other words,extend radially from the tympanum axis and at an angle to the plane ofthe wall of the conical tympanum 10, such as clearly shown in Fig. 3,These extensions or projections 16 are tightly engaged and rigidlysupported by being clamped between the frame 11 and clamping ring 12.The supporting frame 11, clamping ring 12 and arms 14 are all preferablyformed of a non-metallic material and as mentioned the supporting frameand tympanum are so designed that the effective outside diam eter of thetympanum indicated by the line 15 is spaced from the inside periphery ofthe supporting frame 11. By reason of this latter construction andfurthermore owing to the readily flexible extensions angularly arrangedwith reference to the wall of the tympanum vibrations transmitted tothe. tympanum will cause a free vibration of the tympanum both fore andaft or in both directions, without liability of any distortion of thetympanum such as a buckling thereof adjacent its periphery. During thevibratory movements of the tympanum the displacement thereof fore andaft is compensated for by the flexing of the projections or extensions16 along that part of these extensions which extends from the innerdiameter of the frame 11 to the outer peripheral' line 15 of thetympanum 10. An exaggerated indication of this compensating movement ofthe extensions 16 is indicated in Fig. 5. j

The features of this invention thus far described are common to bothforms of construction herein illustrated, as will be clearly apparentfrom a comparison of Figures 3 and 5. Likewise the connection betweenthe diaphragm actuating element and either the tympanum 10 or theinverted intermediate cone or actuating member yet to be described,

is also identical. A description of this invention follows.

The diaphragm actuating element 17 which is actuated by the soundvibrated mechanism, which latter mechanism may be either mechanical asin honographs or electrical as in radios, pre erably extends coincidentwith the axis of the tympanum as" clearly illustrated in Figures 3 andThis element 17 is externally threaded as indicated at 18 to receivespaced clamping nuts 19 and 20. Fitments 21 engage the apex of the coneand clamp the same therebetween, these fitments being maintained inclamping position with reference to the cone by means of a compressiblenon-metallic sleeve of material 20 arranged on the element 17. Thissleeve has one end thereof compressed by means of the nut 20 to form acircumferential shoulder 23 which abuts the ends of the fitments to thusurge the outer fitment 21 into clamping engagement. The other end nut 19to form a circumferential shoulder 24 which bears against the innerfitment 21 to urge the same into clamping position. It should be notedthat the diameter and wall thickness of the sleeve 22 is such that thefitments 21 are spaced from the element 17 as well as from the nuts 19and 20 so that under no circumstances will there be any surface contactbetween these parts. This sleeve of non-metallic material 22 acts as atone modifier andprevents thin metallic and consequently extending in anopposite direction to the apex 26. The body of the mem ber 28 ispreferably cut away at a plurality of points as indicated at 29 so as tomake this cone of a substantially skeleton or perforated naturemaintaining however, both the outer periphery and the inner peripheryadjacent the apex preferably unbroken or.

continuous. The diaphragm actuating element 17 is connected to the apexof cone 28 by the fitments 21 as previously described. The openings 29in the cone 28 permit sound waves caused by a vibration of the tympanumbetween the circumferential line 25 and the apex 26 to freely passbackwardly through this member 28. \Vhile the member 28 is shown anddescribed as substantial ly cone-shaped it will be apparent that con.structions involving, for instance, a plurality of converging arms or askeleton structure having its periphery and apex continuous andconnected by arms, may be utilized with equal effectiveness.

The construction just described is conducive of greater sensitivenessbecause the vi-v brations are transmitted through the member 28 to theconical tympanum 10 at a cir eumferential point spaced between the apexand effective outer diameter of the tympanum at a point where thetympanum is most flexible. Consequently tonal quality and quantity isassured.

In describing the embodiments of the invention illustrated in thedrawings numerous details not essential to the accomplishment of theobjects of this invention have been described and it will be readilyapparent that these details may be altered with out departing from thespirit and scope of this invention and furthermore that many of the moreessential features of the invention may also be changed Withoutsacrificing any of the advantages of the invention and fifty percent orless ofvtheieffe'ctive outside periphery of said tympanum.

etozthis end reservation ism'ade to makesuch ichanges andniodificationsas may coine'within the purview of the accompanyingrl-aims.

hat I claim as my invention is:

1. .In an acousticalmdevice', a. tympanum support, a tympanum and spacedperipheral projections on said tympanum and means for rigidlyconnecting'the .ends of said -projections to saidsupport','the totalcircumferential width of said projections 'occupying periphery of. saidtympanum.

2. In an acoustical device, a tympanum support,a-conical'tynipanuinandperipheral extensions, perpendicular to the axisofthe tympanum and means forrigidly connecting the ends of thesame tosaid'ztsupport, the

total width of said extensions being. fifty percent or lcss'than theeffective. outside 1 385 3. In an acoustical device, a.circular'tympanum support, a conical tympanum and peripheralextensions, perpendicularzto the .axis of the tyinpanumurigidlyconnected to said support, the total widthof'said exten o sions beingfifty percent or. less. than the effective outside peripherycof said'tympamini.

4. In an acoustical device, atympanum support, a conical'tympanum andperipheral a 'GXtGIlSlODS, perpendicular to. the axis of'the tympanumand extending from thereffective "outside periphery thereof for--.connecting sanieto saidsupport, the total widthof said extensionsbeing. fifty. percent: on lCSSTtllELDid the effective-outsideperiphery'ofsaid tympaiium.

Iii an acoustical device, a circular tympanum support, a conicaltympanum and readily flexible peripheral extensions, perpendicular tothe axis of the tympanum rigidly connected to said support, the total:width ofsaid extensions being'fiftypercent or less than the effectiveoutside'periphery of said tympanum.

B32110 6. In an acoustical device, a conical diaphragm, apluralityof-peripheral extensions on said diaphragmand a support rigidlyengagingsaid extensions. and -peripherally spaced from the effective outsideperipheryzg m of said diaphragm, thetotal width ofsaid extensions beingfifty )ercent"or.-less than the effective outside periphery of said dia-7 .Inan acoustical device, a substantiallyia zo conical tympanum, and arelatively inverted substantially conical actuating member secured tosaid tympanum and affording means for connection to a vibrationtransmission element. 39125 8. In an acoustical device, the combinationwith a conical tympanum, of a relatively inverted substantiallycone-shaped member connected to said tympanum at a point spaced from theapex of said tynipaiiunn'sliio the vibrations being conducted to saidtympanum through said inverted cone-shaped member.

9. In an acoustical device, the combination with a conical tympanum, ofa relatively inverted cone-shaped member secured .thereto at acircumferential point spaced from the apex of said tympanum, and avibration transmission element connected to said inverted cone-shapedmember.

10. In an acoustical device, the combination with a conical tympanum, ofa relatively inverted cone-shaped member peri herally rigidly securedthereto at a circum erential point spaced from the apex of saidtympanum, and a vibration transmission element connected to saidinverted cone-shaped member.

11. In an acoustical device, the combination with a conical tympanum, ofa relatively inverted perforated cone secured thereto at acircumferential point spaced from the apex of said tympanum, and avibration transmission element connected to said inverted cone.

12. In an acoustical device, a conical tympanum, a relatively invertedcone having its periphery connected to said tympanum at acircumferential line intermediate the apex and periphery of saidtympanum, and a diaphragm actuating element non-metallically connectedto said inverted cone.

13. In an acoustical device, a conical tympanum, a relatively invertedcone having its periphery connected to said tympanum at a.circumferential line intermediate the apex and periphery of saidtympanum, and a diaphragm actuating element non-metallically connectedto the apex of said inverted cone.

14- In an acoustical device, a conical tympanum, a relatively invertedcone secured at its periphery to said tympanum on a circumferential linespaced from the apex of said tympanum, a diaphragm actuating elementattached to the apex of said inverted cone, readily flexible spacedextensions on the periphery of said tympanum located perpendicular tothe axis thereof, a. nonmetallic frame rigidly engaging said extensionsfor supporting said tympanum, said frame being peripherally spaced fromthe effective periphery of said tympanum.

In testimony whereof I aflix my signature.

REX O. DARNELL.

